Summary

Robust procedure for variable selection in linear model closely related to the all possible model approach is described. Method combines idea of α-acceptability and principle of coherence and use the class of γ-trimmed least squares estimators as the basis for evaluation of estimates.

COmputer-STored Ambulatory Record (COSTAR) is an automated medical record, fiscal management and reporting system, developed in the mid-1970s for use in ambulatory care settings. Its flexibility, full functionality, low cost, and transportability held great promise for wide system dissemination in the 1980s. Reportedly, over 150 health organizations have installed COSTAR worldwide. In reality, this number represents a small fraction of the potential market. Several factors are listed below as contributing to the slower than expected dissemination. Of major importance may be that COSTAR—written in the MUMPS language—could not be installed on IBM hardware. Recently, however, third-party software houses announced MUMPS operating systems that allow COSTAR to run in a multiuser environment on the IBM PC/AT. Developments in the microcomputer field that may impact on the dissemination of COSTAR are described in this paper in addition to early experiences at MITRE with COSTAR on the IBM PC/AT.

The purpose of this paper is to illustrate the advantages of designing computer-based motor controllers together with innnovative motors, such that maximum controller/motor system benefits are obtained. Specifically, this paper describes how a computer-based controller/drive system for powered wheelchairs has been designed and is being built and tested. This type of integral controller/drive system has been possible to build into a wheelchair only with the advent of the microprocessor-based feedback motor controller. The type of motor chosen for this project was a linear synchronous motor (LSM), which is highly efficient (90%+) and could easily be made an integral part of a wheelchair wheel, providing a “no-moving-parts” drive system. However, an LSM cannot be variable-speed-controlled without knowledge of, and controlled adjustment to, the absolute rotor versus stator position at each point in time. Microprocessor-based feedback motor controllers make precise, efficient control of LSMs possible at a reasonable cost. In addition, this combination of controller and motor provides a very flexible wheelchair controlldrive system that may be easily programmed to suit the needs and necessities of the wide variety of over 200,000 persons now using powered wheelchairs.

Most of the proposed econometric models for a single and isolated market in disequilibrium are variations of the canonical disequilibrium model (for an overview see Quandt (1982)). This model consists of a demand and a supply equation
(1a)
$${\rm D}_{{\rm t}\,} \,{\rm = }\,{\rm f(x}_{\rm t}^{\rm D} )\, + \,{\rm u}_{\rm t}^{\rm D},$$
(1b)
$${\rm S}_{{\rm t}\,} \,{\rm = }\,{\rm g(x}_{\rm t}^{\rm s} )\, + \,{\rm u}_{\rm t}^{\rm s},$$
where t is time index, D is demand and S is supply. XD and XS are vectors of independent variables appearing in the demand function f and the supply function g, respectively. The functions f and g must be derived from theoretical considerations about the considered market. They might be non-linear but they contain unknown coefficients which have to be estimated. uD and uS denote the error terms. They are assumed to be serially uncorrelated and independently normally distributed:
(2)
$${\rm u}_{\rm t}^{{\rm D} } \;^\sim \;{\rm N(0,}\sigma _{\rm D}^{\rm 2} )\;\;,\;\;{\rm u}_{\rm t}^{{\rm S} }\;\;^\sim \;\;{\rm N(0,}\sigma _{\rm S}^{\rm 2} ).$$

In Sweden most of the health-care is provided by the County Councils. There are 23 County Councils and three independent cities and they are semi-independent from the Ministry of Health and Social Affairs.

Switzerland is a federation of 26 states and semi-states having their own autonomy. A few major questions such as defense, foreign affairs, custom, money, transportation and telecommunication have been delegated by the cantons to the federal state. But many other questions are remaining at the level of the cantons (our states) with very little influence of the federal level on these questions. Among these questions there is police, laws, education and health care.